Thermodynamic properties of aluminum monooxycarbide Al2OC

Klimov, V. L.; Bergman, G. A.; Karlina, O. K.

doi:10.1134/s0036024406110240

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…The information regarding the conversion of Al 2 OC to AlN is quite limited in the literature. − However, the XRD result in this work clearly indicated that this conversion was thermodynamically allowed during high-temperature transformation of metallized plastic packaging waste (Figure ); thus, this conversion can be simplified as This reaction is also experimentally supported by the continuous emission of CO over the course of the reaction (Figure ).…”

Section: Resultsmentioning

confidence: 56%

“…00-036-0149) was confirmed by the presence of peaks at 32.8, 49.4, 58.5, and 65.8°. The possible pathway for the formation of this phase was the reaction of aluminum with carbon monoxide generated from the decomposition of PET Note: the Gibbs free energy change could not be calculated due to the lack of thermodynamic data for Al 2 OC in the literature. − …”

Section: Resultsmentioning

confidence: 99%

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Mechanistic Evaluation of Single-Crystalline Aluminum Nitride Nanowire Synthesis from Plastic Waste

Yin

Wang

Kong

et al. 2021

ACS Sustainable Chem. Eng.

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One-dimensional aluminum nitride (AlN) nanowires are of great interest because of their unique large band gap and low dimensionality, which make them promising for novel molecular electronic devices and functional composites. However, commercialization is still restricted by the high manufacturing cost and feedstock requirements. Although the feasibility of the synthesis of AlN nanowires from metallized plastic packaging waste has been reported in the previous work, essential information on the synthetic mechanism and nanowire growth characteristics remains unclear. In this work, we have characterized the intermediate solid products to show the initial direct nitridation of the aluminum foil, followed by the formation of aluminum oxide (Al 2 O 3 ), aluminum carbide (Al 4 C 3 ), and aluminum monoxycarbide (Al 2 OC) that are ultimately transformed into AlN in a high yield. This mechanism takes place under an atmosphere of reducing gasses evolved during the decomposition of the plastic components in the waste. The growth of AlN nanowires was monitored during nucleation, crystal growth, and propagation, and finally, conversion from polycrystalline to single-crystalline AlN with an aspect ratio greater than 100 was required for device applications.

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Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Mechanistic Evaluation of Single-Crystalline Aluminum Nitride Nanowire Synthesis from Plastic Waste

Yin

Wang

Kong

et al. 2021

ACS Sustainable Chem. Eng.

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“…When these elements are added, polytypoid‐type crystals, solid solutions such as AlN–Al 2 OC, and composite materials including AlN–Al 2 O 3 can be formed. In terms of thermodynamic studies, including phase stabilities, phase diagrams, and thermodynamic datasets, AlN‐based systems such as SiC–AlN, AlN–Al 2 OC, SiC–AlN–Al 2 OC, AlN–Al 2 OC–Al 2 O 3 , SiC–Al 2 OC, Al 2 O 3 –Al 4 C 3 , AlN–Al 4 C 3 –Al 2 O 3 , Al 2 O 3 –Al 4 O 4 C–Al 2 OC–Al 4 C 3 , Al 4 C 3 –AlN–SiC, and Al–C–O systems have been well explored. Therefore, the phase stability of the Al–C–O system is already clarified.…”

Section: Introductionmentioning

confidence: 99%

Combustion synthesis of AlN doped with carbon and oxygen

et al. 2018

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Carbon-and-oxygen-doped AlN specimens were prepared by combustion synthesis using Al, graphite, and AlN. Graphite addition changed the product color from white to blue. By XRD, the lattice constant increased slightly with increasing carbon content. Blue AlN powder was synthesized with a molar ratio of the diluent AlN of 0.2-0.5 with a fixed graphite content of 0.05. At an AlN molar ratio exceeding 0.6, carbon was not successfully incorporated due to the lower reaction temperature. Calcination at 800°C in air removed residual graphite without changing the crystal structure or product color. Oxygen, nitrogen, and carbon analyses revealed that blue AlN powders contained 0.45-0.54 mass% carbon and 1.4-1.6 mass% oxygen, while the undoped AlN contained 0.021 mass% carbon and 0.94 mass% oxygen. The origin of the white-to-blue color change was investigated via reflection measurements. Blue AlN exhibits an absorption peak at 634 nm (1.96 eV). From first-principles electronic structure calculations, the C-doped AlN and carbon-and-oxygen-doped AlN with a 1:1 ratio could be classified as p-type, whereas the O-doped AlN and 1:3 carbon-and-oxygen-doped AlN were n-type.One reason for the absorption peak at 634 nm may be a transition from the conduction band to an upper unoccupied state. These results suggest the possible control of optical and electronic properties of AlN via carbon-and-oxygen doping. K E Y W O R D Saluminum nitride, combustion synthesis, dopants/doping

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“…The thermodynamic functions presented in Table 1 have been recommended for peforming calculations [10]. These functions were determined from a re-examination of the estimates of the thermodynamic properties of aluminum oxycarbides using the phase diagram of the system Al 2 O 3 -Al 4 C 3 .…”

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confidence: 99%

Characteristics of thermochemical processes in the system C-Al-TiO2 during reprocessing of reactor graphite

Karlina¹,

Klimov²,

Pavlova³

et al. 2006

At Energy

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A thermodynamic analysis and laboratory investigations are performed of the thermochemical processes occurring in the system C-Al-TiO 2 during the reprocessing of reactor graphite. The conditions under which hydrolytically unstable aluminum oxycarbides are formed in the final product are determined. The influence of air and moisture in the initial charge and the composition of the surrounding medium on the characteristics of the process leading to the synthesis of the final product is investigated.It has been shown that the self-maintaining high-temperature synthesis technology based on the reaction 3C(graphite) + 4Al + TiO 2 = 3TiC + 2Al 2 O 3(1)is promising for reprocessing irradiated reactor graphite [1-3]. Preliminary laboratory investigations and a thermodynamic analysis of the reactions in the system C-Al-TiO 2 have been completed [3]. Thermodynamic calculations of the composition of the reaction products in the system indicated have established that carbon monoxide forms in the gas phase. Analysis of samples of the gas phase also showed other constituents besides oxide: H 2 and CH 4 . x-Ray diffraction analysis of the condensed reaction products in the system C-Al-TiO 2 showed that hydrolytically unstable aluminum oxycarbide is present for certain ratios of the initial components [3]; this oxycarbide was neglected in the thermodynamic analysis because the required thermodynamic functions are not avaialble in the reference literature. In this connection, additional thermodynamic and experimental investigations of the thermodynamic processes occurring in the system C-Al-TiO 2 are required. Thermodyamic Analysis. It is known that the aluminum oxycarbides Al 4 O 4 C and Al 2 OC are formed when aluminum oxide interacts with carbon [4]. They also form when the oxide interacts with aluminum carbide [5]. Thus, aluminum oxycarbide forms in the system C-Al-TiO 2 under appropriate conditions, as has been observed experimentally [3]. In order to take account of the possibility of the formation of aluminum oxycarbides when performing calculations, it is necessary to know their thermodynamic properties. At the present time, there are no experimental data on the thermodynamic properties of aluminum oxycarbides. There are only estimates of the formation enthalpy, heat capacity, and entropy for tetraaluminum tetraoxycarbide Al 4 O 4 C and dialuminum oxycarbide Al 2 OC [6,7]. However, the thermodynamic functions calculated for aluminum oxycarbides on the basis of these data [8] do not permit reproducing the phase diagram of the system Al 2 O 3 -Al 4 C 3 [9].The thermodynamic functions presented in Table 1 have been recommended for peforming calculations [10]. These functions were determined from a re-examination of the estimates of the thermodynamic properties of aluminum oxycarbides using the phase diagram of the system Al 2 O 3 -Al 4 C 3 .

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Thermodynamic properties of aluminum monooxycarbide Al2OC

Cited by 6 publications

References 13 publications

Mechanistic Evaluation of Single-Crystalline Aluminum Nitride Nanowire Synthesis from Plastic Waste

Mechanistic Evaluation of Single-Crystalline Aluminum Nitride Nanowire Synthesis from Plastic Waste

Combustion synthesis of AlN doped with carbon and oxygen

Characteristics of thermochemical processes in the system C-Al-TiO2 during reprocessing of reactor graphite

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